The present invention relates to an envelope capable of airtightly maintaining the interior, an image-forming apparatus using this envelope, and a manufacturing method of the envelope.
In the envelope capable of maintaining the interior in a vacuum (pressure reducing state), frit (low melting point glass) is conventionally used as a bond in a joining portion of a face plate (phosphor substrate), a rear plate (electron-emitting substrate) and an outer frame.
Namely, a frit layer is formed as the bond in the joining portion and is next burned so that the joining portion is airtightly sealed and attached and the interior of the envelope can be maintained in a vacuum. In this seal attachment of glass using frit, burning at about 400 to 500xc2x0 C. is required in the atmosphere (normal pressure).
In an image-forming apparatus generally utilizing electrons, it is necessary to arrange the envelope constructed by the face plate as a glass member, the rear plate and the outer frame and maintaining the vacuum (pressure reducing) atmosphere, an electron source for emitting electrons, its driving circuit, an image-forming member having a phosphor, etc. for emitting light in collision with electrons, an accelerating electrode for accelerating the electrons toward the image-forming member, its high voltage power source, etc.
FIG. 19 is a perspective view of the image-forming apparatus using an electron-emitting device disclosed in Japanese Patent Application Laid-open No. 8-83578. FIG. 20 is a cross-sectional view taken along the line B-Bxe2x80x2 of this image-forming apparatus.
As shown in FIG. 19, a rear plate (electron-emitting device substrate) 1701 and a face plate 1702 are joined (or sealed and attached) to each other in a joining portion to an outer frame 1703 through frits 1704, 1705. In this figure, the rear plate 1701 is made of blue plate glass, and the face plate 1702 is made of blue plate glass, and the outer frame 1703 is also made of blue plate glass. Reference numerals 1706, 1707 and 1708 respectively designate upper wiring, a device electrode (upper wiring side) and an electroconductive thin film including an electron-emitting portion. Reference numerals 1709 and 1710 respectively designate a phosphor and a metal back. Lower wiring and a device electrode (lower wiring side) are not illustrated.
As disclosed in Japanese Patent Application Laid-open No. 9-082245, there is a case in which a getter is arranged to maintain the vacuum in the image-forming apparatus using a flat envelope as in a thin type image-forming apparatus.
An object of the present invention is to realize a preferable envelope, a preferable image-forming apparatus and a manufacturing method of the preferable envelope.
One of the inventions of an envelope in the present application is constructed as follows.
Namely, the present invention resides in an envelope constructed by combining plural members and airtightly maintaining an internal space with respect to the exterior, wherein the envelope has a joining portion airtightly joining the members to each other by a sealant having a seal function, and the airtight joining is reinforced by an adhesive having an adhesive function.
Here, the meaning of airtightly maintaining the internal space with respect to the exterior is that the internal space is independently held in an allowable range with respect to the exterior. For example, if the internal space is in a pressure reducing state, the above meaning is that the invasion of substances from the exterior is restrained in an allowable range. When there is a predetermined substance in the internal space, the above meaning is that the invasion of substances from the exterior is restrained in an allowable range, and leakage of the predetermined substance from the internal space to the exterior is restrained in an allowable range.
The above sealant may not have the adhesive function, but preferably has the adhesive function to a certain extent.
In the above invention, the function of the sealant can be suitably fulfilled. A condition in manufacture is particularly strict in a material having the seal and adhesive functions as a unit. However, the envelope having preferable characteristics can be realized in a preferable condition by using the sealant and the adhesive.
In particular, the above adhesive is preferably arranged in the above invention such that the adhesive is in contact with the above joining portion.
Further, in each invention mentioned above, the above adhesive is preferably arranged outside the internal space airtightly maintained by the above sealant. This construction is particularly preferable when no substance emitted from the adhesive is desirable with respect to the internal space in comparison with a substance emitted from the sealant, and when an influence on the internal space due to the undesirable substance emitted from the adhesive with respect to the internal space is larger than an influence on the internal space due to the undesirable substance emitted from the sealant with respect to the internal space.
In each invention mentioned above, the above sealant is preferably formed by a material able to perform a seal process at a temperature equal to or lower than 400xc2x0 C. Further, the above sealant is preferably constructed by a material having a melting point equal to or lower than 400xc2x0 C.
The above sealant preferably includes a metal, and is also preferably formed by a metal or an alloy. In particular, In can be preferably used as the metal.
In each invention mentioned above, a surface processing material may be also arranged in a position in which the above members are in contact with the above sealant. Wettability with the sealant is improved by the surface processing material, and the sealant can be more reliably sealed.
Further, the present application includes the invention of an envelope having an electron source within the interior of the envelope of each invention mentioned above.
Further, the present application includes the invention of an image-forming apparatus having the envelope of each invention mentioned above and an image-forming member arranged within the envelope.
In particular, the electron source is arranged within the above envelope, and the above image-forming member preferably forms an image by irradiating electrons outputted from the electron source. Further, a control electrode for controlling the above electrons may be arranged therein. For example, a grid electrode and an anode electrode are preferably used as the control electrode.
A member for emitting light by electroluminescence (EL) may be used as the image-forming member.
One invention of a manufacturing method of the envelope included in the present application is constructed as follows.
Namely, the manufacturing method of the envelope of the present application is a manufacturing method of an envelope constructed by combining plural members and airtightly maintaining an internal space with respect to the exterior, wherein the manufacturing method includes a first process for airtightly joining the members to each other by a sealant having a seal function and a second process for reinforcing the airtight joining by an adhesive having an adhesive function.
In particular, the second process is preferably performed after the first process.
Further, the present application includes the following invention as an invention of the envelope.
Namely, the present invention resides in an envelope comprising a face plate, a rear plate arranged oppositely to the face plate, an outer frame arranged between the face and rear plates and surrounding a circumference, a face plate joining portion for joining the outer frame and the face plate, and a rear plate joining portion for joining the outer frame and the rear plate to each other. The face plate joining portion and/or the rear plate joining portion include a sealant having a seal function and an adhesive having an adhesive function.